Ships throughout the world must operate in a wide variety of sometimes hostile areas to conduct their mission. Of particular concern is the possibility of terrorist threats such as underwater swimmers or autonomous vehicles that may be used to plant explosives or otherwise sabotage ships.
Military ships presently deter this threat while moored or dockside by detonating small explosive charges beneath the ship. This procedure is hazardous to the ship""s crew, disrupts onboard routines and requires the handling and storage of additional explosives. Additionally, the environmental impact of such explosions is undesirable and often may be unacceptable to the host port or country. Passive listening detection methods are generally unsuitable in harbors because of the extensive acoustical noise present.
Commercial ships are even more vulnerable from such threats as they generally do not have the expertise or ability to conduct explosive deterrents and do not have the sophisticated sonar systems that would be required to attempt passive detection if it were feasible. Also, it would be economically unfeasible for commercial ships to invest large sums of money in such protection measures.
What is needed is a system that could provide all surface ships, military and commercial, and submarines with a detection and self-defense capability against underwater swimmer threats.
In accordance with the invention there is provided a new and improved underwater detection and deterrent system that includes numerous anodes that distribute current in the water surrounding an object that is to be protected. Additionally, there are numerous electrical field sensors for sensing the current flow in the water that is emanating from the anodes. A power supply supplies a range of current to the anodes depending on the inputs from a controller. The controller receives current signals from the sensors and generates various control signals for setting the level of current supplied by the power supply to the anodes and for causing some form of alarm to be displayed or sounded.
In a preferred arrangement, the underwater detection and deterrent system uses anodes that are located on and insulated from the hull of a ship. Optionally, the sensors may also be located on the hull of a ship. The controller for the system may be either implemented in hardware or it may preferably incorporate a microprocessor system that runs software. In a preferred arrangement, the underwater detection and deterrent system""s current level supplied to the anodes may be manually selected. Optionally, the underwater detection and deterrent system may include an alarm display that has both audible and visual indicators for indicating intrusion and location of the intrusion.
In accordance with a preferred arrangement of the invention, the underwater detection and deterrent system includes a net of anodes and sensors suspended in the water by floats. Optionally, this arrangement may be controlled by a microprocessor. In a preferred arrangement, the current level supplied by the power supply to the anodes may be manually selected. The underwater detection and deterrent system includes an alarm display, preferably located on shore, with both audible and visual indicators for indicating intrusion and location of the intrusion.
In accordance with the invention there is provided a new and improved underwater detection and deterrent system that includes a plurality of anodes distributed on the hull of a ship for imparting a current into an electrolyte, for example seawater, and a plurality of sensors distributed on the hull of the ship for sensing the current flow in the electrolyte. The system includes a power supply for supplying electrical power to the anodes and a controller for receiving and processing current signals from the sensors. The controller outputting a level signal for setting the power supplied by the power supply, and also outputting alarm signals. The alarm signals are received by an alarm display system.
In a preferred arrangement the underwater detection and deterrent system has a microprocessor controller. Optionally, the system may include manual selection for the current level supplied to the anodes. Additionally, the underwater detection and deterrent systems alarm display includes both audible and visual indicators for indicating intrusion as well as the location of the intrusion.
In accordance with the invention there is provided a new and improved method for detecting and deterring underwater swimmer threats to a ship. Power is supplied to a plurality of anodes whereby current flows between the anodes at a predetermined level while the current flow is monitored and an alarm is triggered if the current flow changes. The current flow to the anodes is then increased and pulsed in response to the alarm. The current flow may be reset to the predetermined level if the threat goes away. Optionally, the current flow may be substantially increased by manually selecting a lethal level.
For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description, taken in conjunction with the accompanying drawings, and its scope will be pointed out in the appended claims.